<template>
  <div class="swiper-container" ref="swiperRef">
    <div class="swiper-wrapper">
      <div
        class="swiper-slide"
        v-for="(skuImage, index) in skuImageList"
        :key="skuImage.id"
      >
        <img
          :src="skuImage.imgUrl"
          :class="{ active: currentIndex == index }"
          @click="changeCurrentIndex(index)"
        />
      </div>
    </div>
    <div class="swiper-button-next"></div>
    <div class="swiper-button-prev"></div>
  </div>
</template>

<script>
import Swiper from "swiper";
export default {
  name: "ImageList",
  data() {
    return {
      //记录点击小图的顺序
      currentIndex: 0,
    };
  },
  //接收父组件传递的图片数据
  props: ["skuImageList"],
  watch: {
    //使用 watch 监听数据，可以保证数据已经从接口返回，但不能保证 v-for 已经遍历结束
    skuImageList(newValue, oldValue) {
      this.$nextTick(() => {
        new Swiper(this.$refs.swiperRef, {
          //需要前进、后退按钮
          navigation: {
            nextEl: ".swiper-button-next",
            prevEl: ".swiper-button-prev",
          },
          //显示几个图片的设置，参考：https://3.swiper.com.cn/api/Slides_grid/2014/1215/24.html
          slidesPerView: 3,
          //每一次切换图片个数，参考：https://3.swiper.com.cn/api/Slides_grid/2014/1217/27.html
          slidesPerGroup: 1,
        });
      });
    },
  },
  methods: {
    //点击小图切换顺序
    changeCurrentIndex(index) {
      //修改响应式数据
      this.currentIndex = index;
      //利用全局事件总线，通知兄弟组件（Zoom.vue）当前索引值发生了变化
      this.$bus.$emit("getCurrentIndex", this.currentIndex);
    },
  },
};
</script>

<style lang="less" scoped>
.swiper-container {
  height: 56px;
  width: 412px;
  box-sizing: border-box;
  padding: 0 12px;

  .swiper-slide {
    width: 56px;
    height: 56px;

    img {
      width: 100%;
      height: 100%;
      border: 1px solid #ccc;
      padding: 2px;
      width: 50px;
      height: 50px;
      display: block;

      &.active {
        border: 2px solid #f60;
        padding: 1px;
      }
    }
  }

  .swiper-button-next {
    left: auto;
    right: 0;
  }

  .swiper-button-prev {
    left: 0;
    right: auto;
  }

  .swiper-button-next,
  .swiper-button-prev {
    box-sizing: border-box;
    width: 12px;
    height: 56px;
    background: rgb(235, 235, 235);
    border: 1px solid rgb(204, 204, 204);
    top: 0;
    margin-top: 0;
    &::after {
      font-size: 12px;
    }
  }
}
</style>